The present invention relates to a wireless communication device, and particularly relates to a technology that is effective when applied to a wireless communication device capable of performing a plurality of wireless communications with different standards.
Conventionally, for a plurality of wireless communications with different standards for which the same frequency band is used, there are following methods as technologies for preventing degradation of communication quality and communication speed caused by communication contention or interference. First, examples of method of physical avoidance include a method (Frequency Division Multiplex (FDM)) that uses different channels by dividing a frequency band, and a method (Code Division Multiplex (CDM)) that multiplexes communications by assigning different spread codes for the same frequency and the same time. Second, examples of method of probabilistic and dynamic avoidance include a frequency hopping method (Adaptive Frequency Hopping (AFH)) in the same frequency band, and a method that performs transmission control by means of carrier sense (Clear Channel Assessment (CCA)) before wireless communication.
Other effective methods include a method of avoiding power interference by setting an adequate distance between antennas for the respective wireless communications. However, recent downsizing of communication terminals often causes difficulty in adequately separating antennas from each other in a communication terminal. Even if the frequency bands of the wireless communications are separated adequately from each other, it is sometimes impossible to maintain communication quality or communication speed because of the power interference between antennas in a short distance. Particularly, in an audio source receiving device or the like that receives data, such as audio and music, quality is significantly degraded, depending on the communication status of another wireless device. It is more likely that conversing stably or listening to music becomes difficult. In this situation, for example, Japanese Patent Laid-Open No. 2001-217853 (Patent Document 1) discloses a method of avoiding interference between communications with different standards.
With a single communication device capable of performing communications by an IEEE802.11 wireless system and a Bluetooth (registered trademark, the same hereinafter) wireless system, the technology described in Patent Document 1 performs, by time division, data transmission by the IEEE802.11 wireless system and data transmission by the Bluetooth wireless system.